Overview
ISO/TS 21619:2018 - "Geometrical product specifications (GPS) - Types of documents with GPS" defines the basic types of documents used in geometrical product specification (GPS) practice, their relationships and the related terms and definitions. The technical specification establishes a structured approach to separate and link functional specifications (FUN‑SPEC), manufacturing specifications (MAN‑SPEC) and verification specifications (VERI‑SPEC), and explains how any of these can become a contractual specification (CON‑SPEC).
Key topics and requirements
- Types of specifications: clear definitions of FUN‑SPEC, MAN‑SPEC, VERI‑SPEC (both VERI‑SPEC(F) and VERI‑SPEC(M)), and CON‑SPEC.
- Hierarchy and levels: specifications apply at three levels - assembly, sub‑assembly, and component - with FUN‑SPEC at assembly level acting as the master for subordinate FUN‑SPECs.
- Transformation rules: MAN‑SPECs and VERI‑SPECs may be derived from FUN‑SPECs, but transformations must ensure that conformity to the derived specifications guarantees conformity to the master FUN‑SPEC (transformation ambiguity must be managed).
- Traceability and contractual clarity: any specification used as the contract (CON‑SPEC) must include all information needed to meet design intent; suppliers are accountable to the CON‑SPEC.
- Verification and uncertainty: when VERI‑SPECs simplify or modify measurement requirements, the added ambiguity must be reflected in tolerances or the measurement uncertainty statement (see ISO 14253 series).
- Identification practice: the document recommends marking the title block (e.g., FUN‑SPEC, MAN‑SPEC, VERI‑SPEC(M), CON‑FUN‑SPEC) for traceability (see ISO 7200).
Practical applications and users
ISO/TS 21619 is practical for organizations and roles involved in product definition and quality control:
- Designers and engineering teams - to express design intent as FUN‑SPEC and preserve it as the master document.
- Manufacturing engineers and process planners - to derive MAN‑SPECs that realize the FUN‑SPEC while controlling transformation ambiguity.
- Quality, metrology and inspection labs - to prepare VERI‑SPECs consistent with measurement capabilities and uncertainty requirements.
- Purchasers, suppliers and contract managers - to define CON‑SPECs that unambiguously capture contractual requirements.
Benefits include improved communication, clearer responsibilities, better traceability and reduced disputes over specification intent.
Related standards
- ISO 8015 (GPS fundamentals)
- ISO 14638 (ISO/GPS Matrix model)
- ISO 7200 (title block data fields)
- ISO 14253‑1 / 14253‑2 (inspection decision rules and measurement uncertainty)
Referencing these standards ensures consistent application across GPS, measurement and contractual processes.
Keywords: ISO/TS 21619, geometrical product specifications, GPS, FUN‑SPEC, MAN‑SPEC, VERI‑SPEC, CON‑SPEC, specification traceability, ISO GPS matrix.
